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UNIT D STATES PATENT OFFICFQQ N. GRAY BARTLETT, or orniciioofftmxois.

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srncrmca'non forming pm a; Letters Patent No. eooieo'a'atea June 10,1884 7 Application filed December 19, 1893. (No amas.) i

To all whom it may concern:

Be it knownthat I, N. GRAY BARTLETT-fa resident, of Chicago, county of Cook,'and State of Illinois, have invented certain new and useful Improvements in Fire-Extinguishing Oompounds, of which the following is hereby declared to be afull, clear, and exact description, suff cient to enable others skilled in the art to i which said invention appertains to make and use the same.

extinguishing compounds whichcan be advantageously chargedinto tight bomb-like 1871, and No. 282,981, "Harden August 14',

vesselsor hand-grenades, as proposed in Letters Patent No. 117,891, Johnson,,August 8,

1883 Insaid patents the Lpreferred 1 fireQextinguishing material consists of an aqueous solution'ot' carbonic-acid gas retained'under pressure within the vessel, and capable of instant use the moment the vessel is broken.

Thergas was developed .by adding, a suitable .quantity of carbonate salt to. the water and free hydrochloric, sulphuric, or other like acid contained within thevesse'l, after which the mouth of the grenade was "quickly closed and sealed. If for any reasonthe scaling were or became defective, or the vessel were slightly cracked, 'the free carbonic-acid gas existing under high tension would find a vent and the grenade have its fire-extinguishing qualities very materially lessened an d, in deed,

" be well-nigh'valueless. My invcntion is .de-

a when charged into the grenades will notmily signed to offset this source oiloss by prov-id? ing a fire-extinguishing compound which ldevclop thefree carbonic' acid' gas-usual "thereto,'. but will supplement the same by a large additional quantity that remains. in

combined state at ordinary temperatures, but

' becomes immediately available whenthe gre-:

nade isbroken in the' iire. This additional volume of carbonic-acid gas could not possi-v bly exist in free state in the grenade under,

ordinary conditions, since it must inevitably hereinbefore described. The compound is also rendered anti-freezing in quality, so that the grenades can be exposed to a very low degree of cold (1-5 Fahrenheit) without injury or breakage of the bomb, due to congelationof the liquid.

In-t-heprcparation of the compound the pro cess is as follows: To two hundred gallons of cold water are added four hundred pounds of l sodic chloride and two hundred pounds ofv My invention relates more especially to fire ammonia chloride, and when solution is ef- 'i'ected one hundredand fifty-six pounds of muriatic-acid, (189.) Carbonate of potassa is noiv gradually stirred into the-solution in quantity sufiicicn-t to exactly neutralize-the free muriaticacid, (about one hundred and five pounds n'ill bereqniredQ-the stirring-- being repeated with each fresh addition of thc-potass'ic carbonate. The operation should be conducted in theopen air or in connection with a ventilating arrangement capable of car =rying ofi the excess-of carbonic-acid gas,which .placednin the .Vcontaining-vessels' as'soon as practicable. When charged into the grenade, the freecarbonic acid, if any is desired to be developed therein, may be conveniently produced by adding to the liquid, just prior to the hermetical closingof the vessel, an appropri: ate quantity of some acid, by preference generally tartaric acid as being in a solid and therefore convenient condition :foruse, the quantity otf the acid addition being varied to secure any desired degree of pressure within the containing-vessel, though if any high degrce is requisite there 'shouldbe a corresponding increase in the amount oi s odicbicarbon ate prescribed. f V 'T 1 ".lhe compound thusprepared derives its anti-freezing qualities from the presence of the chloride of sodium, potassium, endemmonium combined in such proportions as to saturate the solution at the low temperature. which it is to withstand (-15 Fahrenheit) without freezing. The chloride of potaes nm is not introduced into the solution in th state as'such, but is formed directlythereiu A m duced a very low degree of temperature in the Byreason, therefore, of the absorptive capacity by the reaction of the hydrochloric acid upon the potassic' carbonate. Aside from the ad vantage, commercially speaking, in way of economy, another very important benefit results from this mode of preparing the potassic chloride. At the stage in the process where the potassic carbonate is added the chlorides of sodium and ammonium have already been dissolved, and by their admixture have pro liquid, (about 35 Fahrenheit.) In this condition much of the free carbonic acid evolved by decomposition of the potassic carbonate is absorbed and'retained in solution, which at I 5 higher temperature would pass oh and be lost.

of the cold liquid, it becomes approximately saturated with iree carbonic-acid gas, so that upon being charged into the grenade but little tartaric or other acid addition is necessary to develop a pressure of several atmospheres therein, or, in other words, to charge the grenade with as much free carbonic-acid gas asit can safely withstand. Economy in the acid addition and in the quantity of hicarbonate of soda needed is thus insured.

The fireextinguishing qualities of the compound prepared as hereinbefore described in excess of those possessed by an equal quan- *tity. of water are due, first, to the presence of free carbonic-acid gas, and, second, to what 1 has been termed the combined carbonic-acid gas, or, in other wqrds, to the presence of alkaline bicarbonate, (sodic,) which has remainedundecornposed by reason of the comparativelyslight addition of tartaric or equivalent acid made just prior tb the sealing of the grenades. The alkaline icarbonates possess "the property of parting, ith aportion of their 0 carbonic-acid gas when -their'watery solutions are heated, and even before the boiling-point .of water is reached}, Hence when the liquid containing said bicarbonates is thrown upon a burning body the liquid becomes heated and the carbonic-acid gas is evolved indirect contact with the fi e, contributing very efiiciently to its suppression. Again, the chloride of ammonium, designed, priniarilyjfas' anantifreezing ingredient, is a salt which at a temperature of about'669 Fahrenheit passes into vapor. ".lhis salt being dried out in contact with the heated surface, and passing almost mm d telythereatter into .wpolmls con dition, renders latent in the vaporan enormous amount of sensible heat; or, in other words, acts thereby to rapidly cool down the inflamed body. In addition to this very useful cooling property zfthe ammonium salt when passing into a vaporous condition, the. vapor, itself, of which several gallons are evolved from each pint of 'liquid containing said salt, as prescribed, surrounds the burning body, and by excluding an equal volume of air so far reduces the intensity of the combustion. The sodic and potassic chl0rides,ou drying out of the solution in contact with the fire, become fused, and by surface-coating the material exclude the air and likewise act to check the fire.

While the proportions of the several ingredientshereinbefore specified may-be varied without materially affecting the scope of the invention, it is believed that the best results are attained by adhering to the formula and mode of preparation stated. An obvious sub- 7 5 stitution would seem to be in the addition of ammoniac or potassic bicarbonate, or both, to the quantity of sodic bicarbonate, so that thesolution would become saturated with these salts as well, and the quantity of carbonic-acid gas in latent condition be correspondingly increased. The effect, however, of any such addition in strong solution of sodic-ehlor'ide and free carbonic acid would be to convert the ammouiac or potassic bicarbonates into chlorides and toproduce an additional quantity of sodic bicarbonate, so that it were better to add this latter salt, as such, at the outset if any supersaturation of the liquid with latent carbonic-acid gas is desired. 5

Having thus described the invention, what I claim as new, and desire to secure by Letters Patent, is-

1. A fire-extinguishing grenade hermetically sealed and containing free carbonic-acid gas and a salt of carbonic acid in solution. therein, substantially as set forth.

2. A fire-extinguishing grenade hermetically sealed and containing a salt of carbonic acid in a solution adapted to remain liquid at 1o o a temperature about or'below zero Fahrenheit, substantially asset forth.

3. A fire-extinguishing -grenade hermetically sealed and containing the alkaline chlorides and an alkaline carbonate in solution therein, substantially as set forth.

-4. A fireextinguishing grenade hermetically sealed containing free carbonic-acid gas, together with the alkaline chlorides, and an alkaline carbonate in solution therein, sub [10 stantiallyas described.

s. GRAY BARTLETT.

' Witnesses:

v JAMES H. Person,

' WM. H. DYnENFoRTH. 

